In the electronics manufacturing industry, a high degree of cleanliness is required to prevent contamination of circuitry and devices, which may cause subsequent electronic failure. A common way of packaging electronic integrated circuits is by encapsulating the prefabricated integrated circuit and a portion of the attached leadframe in a plastics material. Typically this is performed utilising injection molding apparatus, often of the transfer mold variety. Known injection molding equipment employs hydraulic presses, and it is not uncommon for hydraulic fluids to leak from the hydraulic presses, which may contaminate the molds and molded products. Although cleansing of the molds is performed regularly, the cleaning techniques are not always effective in removing contaminating debris from the molds. Furthermore, removal of molds for cleaning is often difficult and time consuming. It is an object of the present invention to overcome these problems.